Efficacy of Tenapanor in Patients With or Without Prior Use of IBS-C Prescription Medications: A Post-hoc Analysis of Phase 3 Clinical Trials.

BACKGROUND

Tenapanor is approved for the treatment of irritable bowel syndrome with constipation (IBS-C) in adults. The impact of prior IBS-C prescription treatment(s) on the therapeutic efficacy of tenapanor is unknown.

AIMS: To assess whether prior IBS-C prescription medication use affected clinical response to tenapanor in pooled data from the phase 3 T3MPO-1 and T3MPO-2 trials.

METHODS

Adults with IBS-C were randomized to twice-daily tenapanor or placebo for 12 (T3MPO-1) or 26 (T3MPO-2) weeks. Patients discontinued use of prior IBS-C prescription medications, which were prohibited per protocol, during screening. Post-hoc analyses evaluated responder rates over the first 12 weeks in patients with and without prior IBS-C prescription medication use. The primary composite responder endpoint was defined as achieving ≥ 1 increase in weekly complete spontaneous bowel movements and ≥ 30% reduction in average weekly abdominal pain score from baseline in the same week for ≥ 6 of 12 weeks.

RESULTS

The pooled intent-to-treat population comprised 600 tenapanor-treated patients, of whom 26 (4.3%) reported prior IBS-C prescription medication use (linaclotide, n = 16; lubiprostone, n = 10), and 599 placebo-treated patients. Among patients with prior IBS-C prescription medication use, composite responder rates were 42.3% (11/26) for tenapanor and 18.8% (6/32) for placebo (p = 0.038). Among patients without prior IBS-C prescription medication use, composite responder rates were 31.2% (179/574) for tenapanor and 21.3% (121/567) for placebo (p < 0.001).

CONCLUSIONS

A clinically meaningful response to tenapanor was observed in adults with IBS-C regardless of prior IBS-C prescription medication use.